Internal combustion engines are used to provide a power source for vehicles, generator sets, heavy mechanical equipment, large tractors, on-road vehicles, off-road vehicles, and the like. An internal combustion engine, such as a diesel engine, a gasoline engine, and a gaseous fuel powered engine, is supplied with a mixture of air and fuel for combustion within combustions chambers of the engine to generate mechanical power output.
Under certain operating conditions, a turbocharger in an internal combustion engine improves overall engine efficiency and provides increased power, particularly during vehicle acceleration. In operation, radial inflow turbines are driven by engine exhaust gas. The turbine then drives a radial compressor that increases the pressure of intake air provided to the engine. The increased density of the intake air enhances the combustion process, resulting in a higher output of power.
Turbochargers typically operate at high speeds and high temperatures. For example, in some engines, the turbocharger shaft may rotate up to 170,000 rpm and the temperature of the compressed air leaving the turbocharger may reach up to 200° C. As a result of these extreme operating conditions, turbochargers are often susceptible to excessive damage and in some cases, even failure. Some common turbocharger problems include damaged turbine blades, air or gas leakage, a restriction or blockage in the air injection, journal bearing failure, oil degradation, contaminated oil or insufficient oil supply.
When the turbocharger is not functioning properly, turbine efficiency may be lowered, the engine may operate unstably, and in extreme cases, engine damage may result. Additionally, some turbocharger problems may cause unsafe operating conditions of the engine or even lead to complete engine failure. Engine designers have therefore been particularly interested in closely monitoring the operation of the turbocharger in an effort to identify problems before they impact engine performance. Early detection of turbocharger problems will provide an opportunity to make operational adjustments, expedite necessary repair or replacement of the turbocharger prior to failure. Early detection of turbocharger problems will also ensure the best engine performance and prolong the service of both the turbocharger and the engine.
Different strategies have been employed to address the issue of detecting a turbocharger problem. The most common strategy used involves monitoring the turbocharger shaft speed to detect an anomaly in the operation of the turbocharger. Direct speed measurement of the turbocharger shaft, however, is difficult. Therefore, in some instances it is more common to use another engine operating parameter that is more easily measured as a surrogate for direct speed measurement. For example, German Patent Publication No. DE 102012212555 A1 describes determining rotation speed data that indicates a rotation speed of a compressor of a high-pressure side charging device (i.e., turbocharger) and detecting a fault in one of the charging devices depending on a threshold comparison of the speed indication. The charge pressure over a specified pressure lead on the output side of the compressor of the high-pressure side charging device is used to determine the turbocharger performance. The error in one of the charging devices is detected corresponding to the charge pressure specified.
However, such approaches require additional equipment and do not fully address the difficulties with monitoring turbochargers of existing engine systems using readily available field data. Thus, there presently exists a need in the art for a more reliable system and process for detecting anomalies in turbocharger speed using available field data such that faulty turbochargers may be identified and repaired or replaced prior to failure. Accordingly, the disclosed system and process is directed at overcoming one or more of these disadvantages in currently available turbocharged engine systems.